Elbow drawbench



Aug. 28, 1951 s. F. KITLICA ELBOW DRAWBENCH 2 Sheets-Sheet l Filed March 14, 1947 PIII n f 7; JNVENTOR..

llg- 28, 1951 s. F. KlTLlcA y 2,565,971

ELBOW DRAWBENCH Filed March 14, 1947 2 sheets-sheet 2 I 33 INVENToR.

I WLM am@ z BY l Patented Aug. 28,*1951 g UNITED STATES PATENT 'OFFICE This invention relates to improvements in elbow Y drawbenches, and more particularly to a inachine for expeditiously producing seamless tubular elbows, return bend pipe fittings and the like.

There are available elbow drawbenches or machines adapted for the successive advancement of a plurality of seamless tubes which are forced over a xedly mounted die mandrel and expanded or formed in accordance with the shape of said mandrel to produce seamless tubular elbows, pipe fittings and other tubular objects. In the available machines of this type the feeding of the successive tubes to the mandrel is accomplished by mechanisms which have reciprocatory movements and hence, the feeding and formation of the tubular stock is not strictly continuous for the reason that upon each rearward reciprocation of the mechanism there is a time lag. ln the available machines the tubular stock is advanced to the die mandrel along a mandrel rod, and due to the fact that the stock must be periodically engaged and forced forwardly longitudinally on the rod by the advancing mechanism, the mandrel rod is ordinarily subjected to severe longitudinal strain. Efforts have been made to protect the mandrel rod against longitudinal movement or strain, and for this purpose clamps have been employed, but in the previous efforts the clamping arrangements have not been satisfactory.

With. the foregoing in mind, it is a primary object of the present invention to provide an elbow drawbench wherein the tubular stock is advanced toward the die mandrel continuously, thereby increasing the speed and efficiency of the4 machine. with the elbow drawbench being further provided withV pairs of clamp members for holding the mandrel rod against longitudinal movement or tension. which clamp members are arranged for swinging disengagement from a position at right angles to the axis of themandrel rod to an inactiveposition substantially parallel to the axis of the mandrel rod, and are so manipulatable during advancement of stock on the mandrel. rod notwithstanding longitudinal strain or tension imposed on the mandrel rod.

A further' object of the invention is to provide a machine of the character described having means for continuously advancing along its mandrel rod a plurality of successively positioned tube sections, with such advancement taking place while the mandrel rod, which supports the die mandrel, is positively held against longitudinal movement or strain. v Afurther object of the invention: is to provide an elbow` drawbench equipped with novel and effective pusher block means for advancing the tubular stock on the mandrel rod toward the die mandrel, the pusher blocks being so associated with continuous driving chains that at the termination of a stock forcing operation the forward pusher block will disengage itself from the mandrel rodY and permit a subsequent pusher block to engage and forwardly propel a subsequent section or load of stock. y

A further object of the invention is to provide an elbow drawbench which may be adjusted to receive tubular stock of varying sizes, which is strong and durable, which is efficient and rapid in operation, and which is well adapted to the purposes described.

With the above and other objects in View, the

invention consists of the improved elbow drawbench and its parts and combinations asset forth in the claims, and all equivalents thereof.`

In the accompanying drawings in which the same reference characters indicate the same parts in all of the views:

Fig. 1 is a fragmentary side view of the improved elbow drawbench, with parts broken away and in section to show structural details;

Fig. 2 is a fragmentary plan View of the machine;

Fig. 3 is an enlarged fragmentary detail sectional view taken on. line 3-3 of Fig. 1;

Fig. 4 is an enlarged fragmentary side View, partly in section, of the rear end of the driving and pusher block mechanism for advancing tubular stock;

Fig. 5 is an enlarged fragmentary detail sectional view taken on line 5 5 of Fig. 1; and

Fig. 6 is a fragmentary detail sectional view taken on line 6-5 of Fig. 5.

Referring now more particularly to the vdrawings, and particularly to Fig. l, it will be observed that the apparatus is supported on a suitable foundation which should include a longitudinal pit or recess to accommodate endless chains l0 and depending pusher blocks I l on the lower eX- tents of the chains I. The foundation has imbedded therein a pair of interspaced longitudinally extending I-beams' I2 joined by transverse beams I3. Mounted on thev inner end portion of the foundation isa massive rigid support I4 which carries pairs of mounting brackets i5 for mandrel rod clamp mechanisms which will be described more fully hereinafter. On the foun-V dation, forwardly of the support I4 is a massive rigid open frame support It. Mounted logitudinally over the supports i4; and IiiA is an elongated mandrel rod Il which at its forward or outer end merges into a die mandrel I8. The latter is of such size and shape as to form tubular stock forced thereover into a desired conlguration for the purpose of producing seamless tubular objects such as elbows, return bend pipe fittings and the like. Obviously, the die mandrel is so connected with the die rod that it may be removed and replaced by another one in accordance with the size of the tube to be formed or the degree of bend required. As is conventional in the art, the die mandrel may be disposed in a furnace (not shown), or the tubular stock may be heated by other means to facilitate the expanding and bending thereof. That portion of the mandrel rod II which overlies the support I4 is formed at spaced positions with shouldered recesses I9 and I9' which are for the purpose of periodically receiving clamp blocks, later to be described, which when engaged with the mandrel rod I'I, restrain the mandrel rod against longitudinal strain. This functioning of the cla-mp blocks occurs when sections of stock are being forced longitudinally along the mandrel rod and onto the die mandrel I8.

Within the open frame support IB, and extending forwardly thereof, is a bearing frame 20 in which there are journalled at its forward and rear end portions horizontal sprocket shafts 2I and 22. Each of the shafts 2I and 22 has fast on its outer ends sprockets 23. The pairs of sprockets on the same sides of the bearing frame 20 have trained thereabout the longitudinally extending endless chains ID, previously referred to. Pivotally associated with the endless chains IIB, at variable intervals, which depend on the length of the stock sections to be advanced along the mandrel rod I`I,' are the previously mentioned pusher blocks II.

The form of a pusher block I I, and the manner t in which it is associated with the pair of transversely spaced chains Ill, is best shownin Figs. 3 kand 4. A pusher block IIhas an angularly shaped and weighted base portion 24, the upper flange of which removably and replaceably carries a plate 25 having a U-shaped recess therein which conforms to the size of the mandrel rod I7. The angular base portion 24 of the pusher' block assembly II has laterally extending flanges, whereby, on the upper extent of the chains IIJ, said base portion of the pusher block assemblage rides in a T-slot '26 formed in the upper face of the bearing frame 2D and is thereby caused to move in a position wherein the grooved block 25 is upright and embraces the mandrel rod I'I in contact with the rear end of a section of tubular stock 2'I immediately forwardly thereof.

It will thus be seen that the pusher block assemblage functions along the upper extent of the endless chains I0, when the chains are being driven, to engage the rear end of a section of stock on the mandrel rod and to push said stock forwardly along the mandrel rod toward or onto the mandrel I8. As will be seen from Fig. 3, there is substantial engagement between the grooved pusher block section 25 and the mandrel rod and substantial engagement between the pusher block section 25 and the stock section. Each pusher block assemblage is pivotally carried by the intermediate portion of a transverse shaft 28 removably engaged at its extremities with links of the chains IU. As viewed in Figs. 1 and 4 of the drawings, the chains I are driven in a clockwise direction, and due to the angular weighted portions 24 of the pusher blocks, along the lower extent 4 of the chains I0, said pusher block assemblages hang in the overbalanced position best shown in Fig. 1. As a pusher block assemblage rides upwardly relative to the rear sprockets 23, the undersurface of the base portion 24 of a pusher block assemblage engages and rides on a, curved apron 29. The apron is so arranged that at the time that the pusher block reaches the upper surface of the bearing frame 20, it is moved into the upright position of Figs. 3 and 4 and its flanged base portion then enters the T-slot 26 whereby the pusher block is maintained in the upright engaging position while being propelled, in its pushing function, along the top of the bearing frame 2Il. When the pusher block in question has reached the forward end of the bearing frame 20 a recess allows the rear end of the pusher block to pivot downwardly and further movement of the same is caused by the movement of the chains IIl over the forward sprockets 23. Then, the pusher block assemblage in question, because ofv its weighted construction, pivotally moves to the position shown in Fig. 1 to disengage the section of stock it has advanced. The spacing between the pusher block assemblages is such that at the same time a rearwardly disposed pusher block assemblage is then in position at the rear of the upper surface of the bearing frame 20 to engage and forwardly advance another section of tubular stock 2l. The endless chain drive and the association of the pusher block assemblages therewith is such that a uniform and continuous pressure is exerted against the rear ends of the stock sections 21 which are being advanced along the mandrel rod I? onto the mandrel I8.

It has previously been indicatedthat the outer end of the mandrel rod I1 carries the mandrel I8 and that the propelled pusher block assemblages continuously move sections of stock 2l along the mandrel rod and onto the mandrel. Obviously, such operations subject the mandrel rod to severe longitudinal strains and stresses such as might cause movement of said mandrel rod and mandrel if no means were provided to counteract this tendency. Therefore, one of the important features of the invention is the provision and functioning of two pairs of mandrel rod clamp mechanisms. VWith reference tov Figs. 1 and 2 of the drawings, the clamp mechanisms constituting the pair at the rear end of the support I4 are designated generally by the numeral 30, while the clamp mechanisms constituting the pair at the forward end of the support I4 are designated generally by the numeral 3|. In operation it is intended that a pair of clamp mechanisms be engaged with the mandrel rod and the other pair of clamp mechanisms be disengaged. The result is that one pair or the other of said clamp mechanisms, depending upon whether stock is being introduced onto the inner end of the mandrel rod or whether stock is being forced forwardly toward the mandrel, is always clampingly engaging the mandrel rod, withv such engagement of the clamping mechanisms being within the shouldered recessed portions I9 or I9 of the mandrel rod. It should also be observed, as will appear more fully hereinafter, that the clamping mechanisms of each pair swing from a position at right angles to the axis of the -mandrel rod to an open position parallel to the axis of the mandrel rod, which is highly advantageous.

' It was previously brought out that the inner and outer end portions of the support I4 carry pairs of mounting brackets I5', and said mount- VM* l ing brackets I5 areprovided with laterally projecting extensions. Each bracket and its extension forms the means for properly mounting one of the mechanisms of a pair of clamps. As each clamp of a pair is constructed similarly tothe other, except that the clamping members of a pair are Loppositely disposed, and inasmuch as the clamping mechanisms of the two pairs 30 and 3| are similar, only one of the clamping mechanisms of a pair will be described in detail, and in this connection, attention is particularly invited to the showings in Figs. 5 and 6.

' Rotatably mounted on the bracket l5 is a vertical shaft 32 on the upper end of which is keyed a mandrel rod clamp 33 shapedas is shown in Fig. 6. The mandrel rod clamp 33. when swung to a position at right angles to the axis of the mandrel rod I'I, engages the shoulder. of the shouldered recess i3 by means of a replaceable insert 34 which conforms to the shape of said recess and shoulder, and cooperates for rod clamping purposes with a companion clamp 33 and insert 34. At the lower end of the vertical shaft 32 is keyed a pinion 35. Rotative movement is imparted to the shaft 32 and clamp 33 by means of a rack 36 coacting with the pinion 35, said rack being actuated by a reciprocatable piston rod 31 vwhich is part of an hydraulic ram assembly 38.

The mandrel rod clamp 33 is formed with an extended portion 39 opposite the rod engaging portion 34. Said extended portion 39 is adapted to coact with a horizontally reciprocatable wedge 4D when the clamping member 33 is in the position shown .in Figs. 5 and 6. The wedge 40, when in the position shown in Figs. 5 and 6 engages the extended portion 39 of the clamping arm,. thereby preventing swinging movement thereof while securely holding said clamping insert in engagement with the shoulder of 'the recessed portion i9 of the mandrel rod i1. Reciprocating motion is imparted to the wedge 40 by means of a piston rod 4l connected thereto which is part of another hydraulic ram assembly 42.

In order to disengage the clamping insert 34 from the shoulder of the recessed portion I3 of the mandrel rod I1 retracting motion is imparted to the piston rod 4| by the hydraulic ram assembly 42 so as to cause the wedge 4i) to move rearwardly, out of engagement with andl clear of the extended portion 39 of the clamping arm 33. With the wedge 48 in its retracted position (as shown dotted in the rear clamp mechanism 3!) of Fig. 2), the clamping arm 33 may be swung from its engaged position shown in Figs. 5 and 6 to its disengaged or open position as shownv by the rear clamp mechanism 30 of Fig. 2. Referring again to Fig. 6, the above-mentioned swinging movement is imparted to the vclamping arm 33 by means of retractive movement of the piston rod 3'1 of the hydraulic ram assembly 38 acting on the rack 3S connected thereto which, coacting ywith the pinion 35, causes .clockwise rotation of the shaft 32 and of the clamping arm 33 connected thereto. It is obvious that the simultaneous swinging movement of one of a pair of clamping arms and inserts coacting against the same shoulder of a recessed portion of the mandrel rod I'l is in a direction opposite that of the other clamping arm and insert.

To briefly summarize the sequence of operations of the improved elbow drawbench, reference is made to Fig. 2 in which the mandrel rod Il is clampingly engaged by the clamping inserts 34 Athen closed by the action of the hydraulic krams 3U thereof,l and lockedin clamping engagement by the wedges 40 thereof which are moved forwardly Ainto, locking position by the hydraulic rams 42 thereof. The clamping arms 33 of the forward assembly 3| are then swung to disengaged or inoperative position in the manner hereinbefore described. With the clamping arms of the assembly 3l in inoperative position, the tu.- bular stock is then moved forwardly to a position in which its rear end will be engaged by the grooved plate 25 of a pusher block assembly. Il. This position is indicated in dot and dash form at 21 in Fig. 1. As soon as apiece of tubular stock has been moved into the last-mentioned position, the clamping arms ofthe assembly 3i are swung to vengaging position, the clamping arms of the assembly 33 are swung to inoperative position and a second piece of tubular stock is introduced onto the mandrelv rod at its rear end and moved to the position 43. The pusher block assembly `Il which moves at substantially constant speed will then have pushed the rst piece of tubular stock from position 21 toward the position shown in dot and dash at 45. While the pusher block assemblies are moving the rst piece of tubular stock forwardly, the .clamping arms of the assembly 36 are in their clamping position, and those of the assembly 3l are intheir inoperative or. kopen position. Consequently the second piece of tubular stock may be moved forwardly to a position in which it will be engaged by the pusher block assembly ll following the one which is advancing the first piece of tubular stock along the mandrel rod Il. The clamping arms of the assembly 3l are then swung to engaging position and those of the assembly 30 are swung to vinoperative position for the introduction of a third piece of tubular stock onto the mandrel rod Il. As the second piece of tubular stock is moved forwardly from position 21 it will engage the rear end of the first piece of stock and force the latter onto the die vmandrel IB whereon it will be formed to the desired configuration.

It will be noted that the operation as above outlined is continuous. At all times the clamping members of either assembly 30 or 3| are clampingly engaged with the mandrel rod, while likewise at all times, successive pieces of tubular stock areA being forced over the die mandrel I8. It will be understood that one of the sprocket shafts '2| or 22 may be extended to a source of power (not shown) whereby the sprockets and endless chains are driven vas desired. The hydraulic rams or jacks used foxl the operation of the wedges and clamping mechanisms may be connected with sources of uid under pressure (not shown) as is conventional in devices of this type, and may be either manually or automatically controlled. It is also obvious that the mandrel rod I1 is subject to replacement according to the size of tubing to be operated on and depending upon the diameter of the mandrel rod i utilized the clamping mechanism inserts 34 are subject to replacement.

' The 'advantage of the swinging clamping arms 33 of the improved drawbench over sliding clamping blocks of prior art machines must be emphasized. The diculty experienced in prior machines, of lsliding the clamping blocks .into and out of engagement with the mandrel rod in a path at right angles to the axis of the mandrel rod, is not encountered in the present improvements. This is true because the clamping arms of the present invention, when swinging from engaged to inoperative position, move away from the shoulder with which they were engaged, in the same direction that the mandrel rod is being forced by the action of the pusher blocks in pushing the tubular stock toward and onto the die mandrel. There is no appreciable friction involved in this disengagement because there is no sliding contact between the clamping inserts and the shoulder of the mandrel. rods against which it acts when clampingly engaged. Similarly, there is no appreciable friction created in the operation of engaging the clamping inserts of the improved drawbench with the shoulder of the mandrel rod against which they act. It is evident that the present mechanism eliminates much wear on both the mandrel rod and on the clamping inserts. The improved mechanism additionally provides an efficient, positive and speedy means for interchange of clamping engagement by the two clamping mechanisms with separated portions of the mandrel rod. whereby tubular stock may be continuously fed onto the mandrel rod, while at the same time tubular stock is being continuously formed to the desired coniiguration on the die mandrel.

T he improved elbow drawbench is furthermore of simple and novel construction, operates eiliciently and expeditiously, and is well adapted for the purposes set forth. What is claimed as the invention is:

1. Clamping mechanism for an elbow drawbench which includes a mandrel formed with spaced-part shouldered recesses, comprising pairs of longitudinally spaced, oscillatable clamp members selectively embraceable with the recessed portions of said mandrel rod, means for swinging said clamp members into and out of said mandrel rod recesses, and additional means for releasabiy forcing said clamp members into contact with the shoulders of said recesses, the swinging movement of said clamp members being in a plane which includes the axis of the mandrel rod, and the clamp members when engaged exerting a force on the mandrel rod and longitudinally thereof to counteract longitudinal strain to which the mandrel rod is subjected during the drawbench operation.

2. Clamping mechanism for an elbow drawbench which includes a mandrel formed with spaced-apart shouldered recesses, comprising pairs of longitudinally spaced, oscillatable clamp members selectively engageable with the recessed portions of said mandrel rod, fluid pressure means forrswing-ing'said clamp members into and out of said mandrel rod recesses, wedges movable into and out of contact with said clamp members for releasably forcing said clamp members into contact with the shoulders of said recesses, the swinging movement of said clamp members being in a plane. which includes the axis of the mandrel rod, and fluid pressure means for moving said wedges.

3. Clamping mechanism for an elbow drawbench which includes a mandrel adapted to have tubes forcefully advanced along the forward end formed toward itsrear end with spaced apart shouldered'recesses, comprising pairs of longitudinally spaced oscillatable-clamp members selectively embraceable with therecessed portions of said mandrel rod, means for swinging said clamp members into and out of said mandrel rod recesses, and auxiliary means movable into and out of contact with said clamp members for releasably forcing said clamp members into contact with the shoulders of said recesses, the swinging movement of said clamp members being in a planewhich includes the axis of the mandrel rod and in the direction of advance movement of tubes on the mandrel to counteract the longitudinal strain :to which the mandrel is subjected by the advance movement of the tubes thereon.

4. Conveyor mechanism for an elbow drawbench which includes a mandrel rod adapted to receive tubes for advancement, comprising an endless conveyor having an operating run continuously moving in the same direction along a forward extent of the mandrel rod, weighted pusher blocks pivotally, s'pacedly carried by said conveyor, said pusher blocks being formed to embrace the mandrel rod when on the operating run of the conveyor and to engage the rear ends of tubes on the mandrel rod to advance the same, and means at the starting end of the operating run of the conveyor for swinging the pusher blocks into embracing relation with the mandrel rod, the weighted formation of the pusher blocks and pivotal mounting of the same causing said blocks to swing free of the mandrel rod at the advanced end of the operating run of the conveyor.

STEPHEN F. KITLICA.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 96,766 Angier Nov. 16, 1869 1,552,062 Krell Sept. 1, 1925 1,918,356 Vogt July 18, 1933 1,960,719 Stibbs May 29, 1934 2,242,332 Taylor May 20, 1941 VFOREIGN PATENTS Number Country Date 547,714 Germany Mar. 29, 1932 

